Dorsal Capsuloplasty in Volar Subluxation of the Distal Radius

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CHAPTER 30 Dorsal Capsuloplasty in Volar Subluxation of the Distal Radius

A. Richard Koch, MD, Tijmen de Jong, MD

Instability of the distal radioulnar joint (DRUJ) may be responsible for reduced hand and wrist function from loss of strength and chronic pain on the ulnar side of the wrist. As Bowers noted in 1991, this condition was believed to be rare but became more and more diagnosed and therefore the subject of much discussion and investigation.¹ At this time, Bowers’ observation is still of current interest.

The ulna is the stable unit of the forearm, supporting the radius and the hand and allowing controlled movement of the radius along its axis and the DRUJ. The bony anatomy of the DRUJ, however, adds very little to stability. A variety of other structures are responsible for stability of the DRUJ. It is currently assumed that these comprise the pronator quadratus, ulnocarpal ligament, extensor carpi ulnaris subsheath, dorsal radioulnar ligament, volar radioulnar ligament, interosseous membrane, the bony anatomy (sigmoid notch), and the DRUJ capsule.²^–¹⁰

The soft tissues, together with normal articular cartilage surfaces of the lower end of the ulna and the medial articular facet of the distal radius, ensure a smooth and complete forearm in pronation/supination.^1,¹¹ This specific movement is provided not only by rotation from the radius about the ulna but can also only be executed when there is a variable degree of dorsopalmar translation.^12,¹³

Garcia-Elias described in his article on soft tissue anatomy and relationships about the distal ulna that the radius in supination rotates and translates dorsally about the stable ulna, whereas in pronation it rotates and translates palmarly.¹⁴ As a result, there is a great variance in joint surface contact of the DRUJ between the sigmoid notch of the distal radius and the articulating surface of the ulnar head. In the neutral forearm position the surface contact is maximal (about 60%). In all other forearm positions there is joint surface contact until it is lost almost completely (less than 10%).¹⁵

A stable DRUJ allows rotation, axial motion, as well as translational movement in the dorsopalmar plane. All these movements are based on the osseous contours around the joint, supported by a complex of surrounding soft tissues, which Bowers ¹ calls the major retaining ligaments. The triangular fibrocartilage complex (TFCC) is considered the major retaining ligament of the DRUJ, with two ligament subsets, the dorsal and volar marginal ligaments (DML-TFC, VML-TFC). These thickenings on the dorsal and volar margins of the central part of the TFCC on the triangular fibrocartilage proper are also referred to as the dorsal and volar radioulnar ligaments.¹⁶ There is experimental evidence^6,^17,¹⁸ suggesting that both palmar and dorsal distal radioulnar ligaments need to be intact to maintain complete stability of the joint throughout the whole range of forearm rotation. The relative contribution of each ligament in stabilizing the DRUJ during pronation/supination remains, however, contradictory.^6,^7,^13,^17,¹⁹

Post-traumatic rupturing, laxity, or attenuation of the suspending soft tissues around the DRUJ may lead to DRUJ instability and cause chronic ulnar wrist pain, with decreased grip strength and a reduced sensation of wrist stability, affecting many activities of daily life. The inability of normal wrist function and subsequent pain may finally result in full work incapacitation.

Most of the current treatment options regarding instability of the DRUJ refer to reconstruction of the TFCC. A great variety of techniques have been published. Adams and Berger have classified these techniques into three categories ²⁰: (1) a direct radioulnar tether that is extrinsic to the joint,²¹ (2) an indirect radioulnar link through an ulnocarpal sling or tenodesis,²² and (3) reconstruction of the distal radioulnar ligaments.^16,²³

In their article, Adams and Berger describe their own technique for reconstruction of both dorsal and palmar radioulnar ligaments, because they believe that gross instability of the DRUJ requires disruption of both ligaments. Reconstruction of both ligaments would therefore be the optimal surgical treatment for post-traumatic, chronic DRUJ instability. For this purpose they use a tendon graft (usually the palmaris longus), which is passed through drill holes in the distal radius and ulna.²⁰

In this chapter we describe the history and fate of 20 of our patients with only limited instability of the DRUJ. The basic cause for instability is a post-traumatic attenuation of the dorsal capsule, which we consider an extension of the dorsal marginal ligament. This instability permits a volar subluxation of the distal radius, resulting in chronic ulnar wrist pain.

Reefing of the dorsal capsule and thereby tightening the DML is our therapy of choice. This surgical approach is a result of a fortuitous observation during arthroscopy and open surgery in a patient with typical complaints of a painful DRUJ instability. As a routine, we perform an arthroscopy to improve our diagnostic differentiation. One of the most striking features during this examination was a clear laxity of the TFCC exclusively in the dorsal part. During the subsequent operation (see later), we observed a notable surplus of soft tissues over the ulnar head just proximal to the DML, becoming most evident when reducing the volar subluxation of the radius with the ulna. This tissue was not only found to be in continuation with the ligamentous part of the TFCC (DML) but also appeared surprisingly strong and sufficient for capsuloplasty.

The Authors’ Experience

Patient Selection

The course of 20 consecutive patient treatments during the period from 2003 until 2005 was analyzed retrospectively. Charts were reviewed for preoperative history and physical findings. Fifteen of the patients were female,¹⁴ and 5 were men. Of this group, 4 patients were excluded. One patient could not be traced for follow-up, 1 patient developed a pain syndrome (although on the radial side of the wrist), and 2 patients were excluded because of the severity of their TFCC degeneration, which became apparent during operation. Nevertheless we attempted a reefing of the DML, which later proved insufficient. In these 2 patients an ulnar shortening was performed in a second operation.

Therefore, 16 patients were included in the study, with an average age of 26 years (range: 9 to 56 years). In 10 patients the dominant wrist was involved. The mean duration of symptoms before first contact in our clinic was 31 months (12 to 108 months). The average follow-up was 12 months (5 to 23 months). All of these patients except 2 had a history of wrist trauma, of whom 6 suffered fractures of the distal radius or scaphoid. They were all treated with closed reduction and casting. None had previous surgery for DRUJ instability.

Physical Findings

We observed that patients suffering from painful DRUJ instability usually presented with painful rotation and ulnar deviation, often in combination with a painful click sensed over the dorsal aspect of the DRUJ while making rotational movements. Most patients complained of a reduced grip strength and periodic sensations of sudden wrist instability, provoked by rotational movements during (heavy) lifting.

In most of the patients, swelling around the ulnar side of the wrist could be observed. Sometimes, the ulnar head, however, was more prominent on the affected side. Subluxation of the extensor carpi ulnaris tendon in the sixth extensor sheet could be excluded. Rotation of the forearm was usually not restricted. Extreme supination was sometimes painful. Flexion and extension were symmetrical on both sides. A painful joint click in active and passive forearm rotation was present in seven patients.

In all patients an increased anteroposterior translation of the DRUJ was found, with passive manipulation, compared with the uninvolved wrist. When performing this maneuver, we ask the patient to lay the flexed elbow on a table with the hand pointing to the ceiling. Bringing the forearm in neutral position with the thumb pointing to the nose, the patient is asked to hold the wrist in full relaxation. Thus, we compare the translation of both wrists in neutral, supination, and pronation to evaluate the severity of instability. With the arm in the same position, we also perform the ulnar compression test. With the wrist in ulnar deviation, force is executed, thus compressing the ulnar side of the proximal row of the carpus against the TFCC. In only three patients, the ulnar compression pain was positive.

All patients had tenderness around the distal ulna, which varied from just distal and palmar of the ulnar styloid, dorsal to the distal edge of the ulnar head, or over the DRUJ.

Imaging

As a routine we obtain posteroanterior and true lateral plain radiographs in radial as well as in ulnar deviation. The lateral radiographs had our interest for objectivation of an altered prominence of the ulnar head, which was the case in six patients. No wrists showed a widening of the joint in the posteroanterior radiograph. There were no signs of earlier trauma to the ulnar styloid process. The joint surfaces of the DRUJ and distal ulna showed no signs of earlier trauma or arthrosis. Before referral to our clinic, arthrography or magnetic resonance imaging (MRI) was performed in two patients. MRI showed a peripheral lesion of the TFCC, and arthrography demonstrated a central leak. Computed tomography was not performed.

Arthroscopy

Every patient in this series was subjected to wrist arthroscopy. A constant finding of the TFCC was observed in those patients who were suspected of having an instability of the DRUJ region. With the scope through the 3-4 portal and the probe via the RU portal, we obtained a clear view of the TFCC. When testing the tension of the TFCC with the probe, it often showed a normal movement (trampoline effect) of the central part of the TFCC; however, there was laxity in the area of the dorsal radioulnar ligament of the TFCC when compressing and pulling it with the curved probe. We often found an excess of fibrous tissue in this area, which was sometimes accompanied by a localized synovitis. To obtain a better view on the dorsal TFCC area we performed an arthroscopic synovectomy, but we have never seen clear tears in that area.

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